Are X-Rays and Visual Exams The Best Tools for Detecting Tooth Decay?

Can Radiographs and Visual Exam Detect Pit and Fissure Caries?

Radiographic and visual examinations are satisfactory if there is a substantial cavitated lesion.  Detecting early pit and fissure caries is challenging.  Radiographic imaging is of minimal diagnostic value because of the large amounts of surrounding enamel[i] [ii].  A number of studies have found the dental explorer inefficient for the diagnosis of occlusal caries.[iii] [iv]  There are a number of the concerns with the use of the explorer in detecting pit and fissure caries:

  • Since cavitation in pit and fissure caries occurs late in the disease process, using an explorer stick to detect caries only finds larger lesions,
  • Probing an occlusal pit or fissure could convert a small lesion into a larger one[v],
  • The probing could produce irreversible traumatic defects in areas that have the potential to remineralize,
  • Probing can inoculate the fissure with microorganisms from other intraoral sites[vi] [vii],
  • A stick or catch with an explorer may be due to fissure morphology or probe pressure rather than a carious lesion.

Can Radiographs Detect Enamel Lesions in Interproximal Areas (Between Teeth)?

Radiographs do perform well in detecting carious lesions in interproximal areas, especially if the area of decay is at least half way through the enamel or into dentin   In terms of early lesion detection, radiographs are not able to detect small lesions in the order of 50 – 100 μ (microns) in the interproximal areas, which could remineralize if detected early and suitable preventive measures instituted[viii].   One study using bitewing radiographs for detection of interproximal caries found 10.6% of enamel caries, 17.8% of dentine caries and 40.2% of deep dentine caries.  This indicated that at best bitewing radiographs could detect deep lesions less than 50% of the time[ix].  This low sensitivity for detection of enamel lesions in interproximal regions is not unusual and may be due to the irregular shape and low contrast of these small early lesions[x].

An extensive review of the literature by Dove[xi] found that “overall the strength of the evidence for radiographic methods for the detection of dental caries is poor for all types of lesion on proximal and occlusal surfaces”.  He further stated that “it is beneficial only if the intervention is the surgical removal of tooth structure and detrimental if it is used for non-invasive remineralization methods”.  Pretty and Maupome in their review of radiographic diagnostic procedures concluded that “for interproximal lesions a clinician using radiographs can be very certain of the lack of disease in apparently sound surfaces (97% specificity) but not as certain that disease is indeed present in suspect interproximal surfaces (54% sensitivity)”[xii].  Radiographs and visual examination are a valid diagnostic tool for the detection of larger lesions[xiii] [xiv] but there is need for more sensitive methods.

X-Rays are a good screening tool for looking at the bone level around teeth or at the edges of deep fillings below the gum line but they do have limitations.   X-Rays and Visual Exam are still common and standard tools for detecting tooth decay but one needs to look at the crystal structure of the tooth in order to detect and measure tooth decay or defects in teeth.  The Canary System offers the solution.

A recent clinical trial led by the University of Texas found that The Canary System found 92% of the decay between teeth while x-rays only found 62% of the lesions.  This study was reported at the March 2015 meeting of the International Association of Dental Research.

Visit http://www.thecanarysystem.com for more information.

[i]  McKnight-Hanes C, Myers DR, Dushku JC, Thompson WO, Durham LC. “Radiographic recommendations for the primary dentition: comparison of general dentists and pediatric dentists”. Pediatr Dent. 1990 Jul-Aug;12(4):212-216

[ii]  Flaitz CM, Hicks MJ, Silverston LM. Radiographic, histologic, and electronic comparison of basic mode videoprints with bitewing radiography. Caries Res. 1993; 27(1): 65-70.

[iii]  Penning C, van Amerongen JP, et al, “Validity of probing for fissure caries diagnosis. Caries Res 26:445-9, 1992

[iv]  Lussi A, “Comparison of different methods for the diagnosis of fissure caries without cavitation”. Caries Res 27:409-16, 1993

[v]  Yassin OM. In vitro studies of the effect of a dental explorer on the formation of an artificial carious lesion.” ASDC J Dent Child. 1995 Mar-Apr;62(2):111-117

[vi] Ekstrand K, Qvist V, Thylstrup, A, “Light microscopic study of the effect of probing in occlusal surfaces”:, Caries Research, 1987; 21: 368 – 374

[vii] Penning C, Van Amerongen JP, Seef RE, ten Cate, JM “Validity of probing for fissure caries diagnosis”, Caries Research, 1992; 26(6): 445 – 449

[viii] Backer DO, “Post-eruptive changes in dental enamel”, J Dent Res 1966; 45: 503 – 51

[ix] Senel, B., K Kamburoglu, K., Ücok, Ö., Yüksel S. P., Özen, T., Avsever, H., “Diagnostic accuracy of different imaging modalities in detection of proximal caries”,  Dentomaxillofacial Radiology (2010) 39, 501–511

[x] Pontual A. A., de Melo, D. P., de Almeida, S. M., Boscolo, F. N., Haiter Neto, F., “Comparison of digital systems and conventional dental film for the detection of approximal enamel caries”,  Dentomaxillofacial Radiology (2010) 39, 431–436

[xi] Dove, S. B., “Radiographic Diagnosis of Dental Caries in Consensus Conference on Dental Caries Management Throughout Life, March 2001, Journal of Dental Education, 2001; 65 (10): 985 – 990

[xii]  Pretty, I. A., Maupome, G., “A Closer Look at Diagnosis in Clinical Dental Practice:  Part 3. Effectiveness of Radiographic Diagnostic Procedures”, JCDA, 2004; 70(6): 388 – 394

[xiii] Li, G., Yoshiura, K., Welander, U., Shi, X-Q McDavid W. D., “Detection of approximal caries in digital radiographs before and after correction for attenuation and visual response. An in vitro study”,  Dentomaxillofacial Radiology (2002) 31, 113 – 116

[xiv] Rockenbach, M. I., Bauer, E., Nilza, V., da Costa, P., “Detection of proximal caries in conventional and digital radiographs: an in vitro study”,  Stomatologija, Baltic Dental and Maxillofacial Journal, 10: 115-120, 2008

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